Marius, the Copenhagen Zoo's healthy 18-month-old giraffe, was euthanized by his keepers and fed to the zoo's meat-eating animals Sunday despite online protests from animal lovers over the plan.

Zoo officials said they killed the animal as part of its policy to prevent in-breeding and keep the giraffe population genetically sound, the Copenhagen Post said.

"Giraffes today breed very well, and when they do you have to choose and make sure the ones you keep are the ones with the best genes," Bengt Holst, the zoo's scientific director, told the BBC.

Zoo officials carried out Marius' killing despite protesters at their gates, a petition that had gained 27,000 signatures and offers from other zoos to take the giraffe.

As dawn broke Marius was given a last meal of a favorite food, rye bread, The Guardian reported. A veterinarian then shot him in the head with a bolt rifle.

Shooting was picked over lethal injection so the meat wouldn't be contaminated, the BBC reported.

As crowd of adults and children watched, the carcass was skinned, dissected over the course of three hours, then fed to the lions and other carnivores. The postmortem was carried on the Internet.

Even as Marius was meeting his fate, an online petition aimed at sparing him was gaining 2,000 signatures an hour, the Copenhagen Post.

"The zoo have produced him so it is their responsibility to find him a home, no matter how long it takes," said Maria Evans, the petition's originator. "They must not be allowed to take the easy option."

Officials at other institutions that had offered sanctuary to Marius expressed sorrow.

"I can't believe it. We offered to save his life," Robert Krijuff, director of a Dutch wildlife park that had made a last-minute offer to take the giraffe, told the BBC. "Zoos need to change the way they do business."

An explanation posted on the Copenhagen Zoo's website said transferring Marius to another European zoo wouldn't help because his genes were too common in the gene pool of European giraffes, raising the risk of in-breeding. The same type of gene-pool management is used at deer parks, the site said.

Zoo officials didn't want to give Marius contraceptives because they cause unwanted side effects on internal organs, and because they wanted to keep their giraffes' reproduction and nurturing behaviors as natural as possible.

Holst told The Guardian he never considered canceling Marius' killing:

"We have been very steadfast because we know we've made this decision on a factual and proper basis. We can't all of a sudden change to something we know is worse because of some emotional events happening around us. It's important that we try to explain why we do it and then hope people understand it. If we are serious about our breeding activities, including participation in breeding programs, then we have to follow what we know is right. And this is right."

CNN filed this video report. Warning: some of the images are graphic; viewer discretion is advised:

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